Random Response Spectrum Analysis of Gravity Dam Classes: Simplified, Practical, and Fast Approach

2018 ◽  
Vol 34 (2) ◽  
pp. 941-975 ◽  
Author(s):  
Mohammad Amin Hariri-Ardebili ◽  
Victor E. Saouma
Keyword(s):  
Fragility Curves ◽  
Response Spectrum ◽  
Input Parameter ◽  
Gravity Dam ◽  
Random Response ◽  
Numerical Techniques ◽  
Gravity Dams ◽  
Response Spectrum Analysis ◽  
Fast Approach ◽  
Demand And Capacity

The seismic risk of concrete dams may be assessed using various numerical techniques, ranging from simplified methods to linear and nonlinear ones. Such methods should be combined with probabilistic concepts to account for the randomness in both demand and capacity. This paper proposes a random version of a simplified response spectrum method (involving equivalent static lateral forces [ESLFs]) for gravity dams by means of propagating uncertainties through the input parameters. Input parameter sensitivity is quantified and the extended procedure is explained step by step. Results are then generalized for the different dam classes. The impacts of sampling size and technique (i.e., pseudo-random and quasi-random) are also discussed. A time-based performance is evaluated and fragility curves are derived. This method may be used during the initial stages of a design process or safety analysis for existing dams.

Static and Dynamic Analysis of Concrete Gravity Dam by ANSYS

2013 ◽  
Vol 438-439 ◽  
pp. 1334-1337
Author(s):  
Xin Zhong Zhang ◽  
Xiao Na Sun ◽  
Ke Dong Tang
Keyword(s):  
Dynamic Analysis ◽  
Flood Control ◽  
Response Spectrum ◽  
Economic Benefits ◽  
Green Energy ◽  
Gravity Dam ◽  
Security Evaluation ◽  
Concrete Gravity Dam ◽  
Response Spectrum Analysis ◽  
Static And Dynamic Analysis

Dam is the most important building in water conservancy, which generates enormously social and economic benefits in the national economy by providing green energy to all walks of the national daily life, and playing a important role in flood control for the safety of peoples lives and properties. However, as dam outburst will bring disastrous consequences to the downstream place, it is very important to ensure the safety of dam. By the large general software ANSYS for static analysis and the response spectrum analysis method for the dynamic analysis, this paper gives the security evaluation of a RCC gravity dam project, and provides some reference for similar engineering analysis.

Implementation of an Efficient RMS Algorithm for Random Analysis in Vibrata™

2012 ◽  
Author(s):  
Cory J. Rupp ◽  
Gregory W. Antal
Keyword(s):  
Response Spectrum ◽  
Random Excitation ◽  
Analysis Tool ◽  
Mean Square ◽  
Memory Usage ◽  
Random Response ◽  
Text File ◽  
Response Spectrum Analysis ◽  
Power Spectral ◽  
Response Method

When analyzing forced dynamic response to random excitation, obtaining root-mean-square (RMS) results without having to compute the underlying power spectral density (PSD) functions can significantly reduce solution time and memory usage. An algorithm for such calculations published by de la Fuente [1, 2] has been incorporated in ATA Engineering’s Vibrata™ program, a GUI- and text-file-driven modal dynamic analysis tool that works with Femap™ and MATLAB® to provide random, transient, harmonic, and response spectrum analysis. This paper describes some of the difficulties encountered in implementing this random response method and how they were overcome. It then shows two examples of the algorithm’s use in Vibrata and compares those computation times and solutions to standard PSD-based computations.

Damage Index Evaluation of Concrete Gravity Dam Based on Hysteresis Behavior and Stiffness Degradation Under Cyclic Loading

2017 ◽  
Vol 17 (01) ◽  
pp. 1750009 ◽  
Author(s):  
MD. Imteyaz Ansari ◽  
Pankaj Agarwal
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Damage Index ◽  
Gravity Dam ◽  
Concrete Gravity Dam ◽  
Gravity Dams ◽  
Cumulative Energy ◽  
Element Analysis ◽  
Hysteresis Behavior ◽  
Concrete Gravity Dams

An assessment of seismic vulnerability of concrete gravity dams based on the fragility curves needs a well-defined damage index (DI) to define different states of damage. The DI formulation for other types of structures is not applicable to concrete gravity dams due to the change in failure mechanism. In this study, a definition of DI based on the factor of safety against sliding is attempted and correlated with the DI formulation based on the natural period of the structure and the maximum crest displacement with cumulative energy dissipation. The proposed DI relies on the nonlinear behavior of the concrete gravity dam model under cyclic testing. The hysteresis behavior is also verified through the finite element analysis by considering the damaged plasticity behavior of concrete.

Geometric Configuration Effects on Nonlinear Seismic Behavior of Concrete Gravity Dam

2018 ◽  
Vol 12 (01) ◽  
pp. 1850003 ◽  
Author(s):  
Md. Imteyaz Ansari ◽  
Mohd Saqib ◽  
Pankaj Agarwal
Keyword(s):  
Nonlinear Dynamic ◽  
Seismic Behavior ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Geometric Configuration ◽  
Gravity Dam ◽  
Concrete Gravity Dam ◽  
Gravity Dams ◽  
Concrete Gravity Dams ◽  
Dynamic Analyses

The effects of geometric configuration on the seismic vulnerability of concrete gravity dam are discussed in the present study. The seismic vulnerability of concrete gravity dams has been represented through fragility curves obtained through incremental dynamic analyses by considering their nonlinear dynamic behavior. Five different geometries of concrete gravity dams are considered and fragility analyses are carried out on the basis of Incremental Dynamic Analyses. The effect of smoothening of re-entrant corners in the geometry of high concrete gravity dam is also presented as a possible solution.

scholarly journals Updated Kriging-Assisted Shape Optimization of a Gravity Dam

Water ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 87
Author(s):  
Yongqiang Wang ◽  
Ye Liu ◽  
Xiaoyi Ma
Keyword(s):  
Surrogate Model ◽  
Computational Cost ◽  
Region Of Interest ◽  
Optimization Procedure ◽  
Optimal Shape ◽  
Small Sample ◽  
Gravity Dam ◽  
Kriging Surrogate Model ◽  
Gravity Dams ◽  
Sample Set

The numerical simulation of the optimal design of gravity dams is computationally expensive. Therefore, a new optimization procedure is presented in this study to reduce the computational cost for determining the optimal shape of a gravity dam. Optimization was performed using a combination of the genetic algorithm (GA) and an updated Kriging surrogate model (UKSM). First, a Kriging surrogate model (KSM) was constructed with a small sample set. Second, the minimizing the predictor strategy was used to add samples in the region of interest to update the KSM in each updating cycle until the optimization process converged. Third, an existing gravity dam was used to demonstrate the effectiveness of the GA–UKSM. The solution obtained with the GA–UKSM was compared with that obtained using the GA–KSM. The results revealed that the GA–UKSM required only 7.53% of the total number of numerical simulations required by the GA–KSM to achieve similar optimization results. Thus, the GA–UKSM can significantly improve the computational efficiency. The method adopted in this study can be used as a reference for the optimization of the design of gravity dams.

Random Response Analysis of a Large-Size Cooling Tower Subjected to the Stationary Earthquake Motion

2013 ◽  
Vol 423-426 ◽  
pp. 1589-1593
Author(s):  
Jia Ning Zhu ◽  
Ya Zhou Xu ◽  
Guo Liang Bai ◽  
Rui Wen Li
Keyword(s):  
Power Spectrum ◽  
Random Vibration ◽  
Cooling Tower ◽  
Response Spectrum ◽  
Power Spectrum Density ◽  
Random Response ◽  
Large Size ◽  
Earthquake Motion ◽  
Spectrum Density ◽  
Random Vibration Theory

The response of a large-size cooling tower with 250m high subjected to the seismic action are investigated by both random vibration theory and response spectrum method. Shell element is taken to model the tower body, and beam element is used for the circular foundation and supporting columns. The earthquake motion input is a colored filtered white noise model and mode superposition method is adopted to analyze the random response of the large-size cooling tower. The paper presents the power spectrum density functions (PDF) and standard deviation of the displacement of the top and characteristic node, and the analysis results indicate that the results of the stationary random vibration theory and the response spectrum method are the same order of magnitude. The power spectrum density function of the bottom node stress is obviously bigger than the one at the top and the throat, and the random response of meridonal stress is dominated at the top. In addition, the peak frequency position of the power spectrum density function is different from the corresponding stress.

Genetic Algorithm for Searching for Critical Slip Surface in Gravity Dams Based on Stress Fields

2013 ◽  
Vol 790 ◽  
pp. 146-149
Author(s):  
Jian Yun Chen ◽  
Shu Wang ◽  
Qiang Xu ◽  
Jing Li
Keyword(s):  
Genetic Algorithm ◽  
Slip Surface ◽  
Safety Evaluation ◽  
Fem Analysis ◽  
Stress Fields ◽  
Gravity Dam ◽  
Critical Slip Surface ◽  
Gravity Dams ◽  
Sliding Stability ◽  
Search Program

Currently, the safety evaluation of gravity dam concentrates on stress and anti-sliding stability of the dam. A lot of research shows that the upper area of the dam is one of the whole dams weakest areas during an earthquake and should be studied in details. In this study, the genetic algorithm and non-linear FEM analysis are combined, then a search program is written to search the critical slip surface in the dams upper area. Finally, the surface which has the least anti-sliding stability coefficient is obtained, the most dangerous slip surface and its anti-sliding coefficient as well as the corresponding time are acquired to evaluate the safety of the dam.

Catastrophic Analysis of Seismic Response of Gravity Dam Sliding along Base Surface

2011 ◽  
Vol 311-313 ◽  
pp. 2164-2168
Author(s):  
Dun Ben Sun ◽  
Qing Wen Ren
Keyword(s):  
Weibull Model ◽  
Gravity Dam ◽  
Stable Region ◽  
Instability Mechanism ◽  
Gravity Dams ◽  
Base Surface ◽  
Instability Problem ◽  
Nonlinear Constitutive Model ◽  
Hysteresis Phenomena ◽  
Sliding Instability

For the instability problem of gravity dam sliding along base surface, cubic nonlinear constitutive model of soft material in base surface is adopted, which is usually expressed by Weibull model. Dynamic Equations of dam sliding along base surface is established. By means of catastrophe theory, the jumping and hysteresis phenomena of the vibration amplitude of the dam is analyzed, the parameter range of stable region in which amplitude doesn’t happen catastrophe is given and the factors which cause amplitude instability are discussed. The results obtained in the paper are of significant value for understanding the sliding instability mechanism of gravity dam under earthquake, as well as guiding the design of gravity dams.

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